Advancements in electronic and computer technology have enabled continued miniaturization of associated components and circuitry. Accordingly, the physical characteristics, e.g., footprint, internal volume, etc., of the computer system have been proportionately reduced to realize those advancements.
Taking advantage of this reduction, many computer manufacturers are developing computer systems that include a multiple instancing of a single component, e.g., multiple microprocessors where previously a single microprocessor was disposed. While multiple instantiations of microprocessors can increase the processing power of the computer system into which they are integrated, it is appreciated that multiple microprocessors also increase the amount of heat generated within the computer system.
Excessive heat can have a detrimental effect upon the function and operation of a computer system. Unless the heat generated from within the computer system is properly dissipated, serious side effects, ranging from sporadic memory loss to total system failure, can occur. Additionally, with the components, circuitry, and physical characteristics of the computer system being reduced, available internal vertical space between components and internal volume space within the computer system are also reduced. In some instances, a reduction in internal volume space may compound the problem of insufficient heat dissipation.
In one attempt to provide additional cooling within a computer system, an additional cooling fan was designed to be plugged into an expansion slot located on the motherboard. While providing some additional internal airflow, this type of approach has shortcomings associated therewith. For example, if the computer system, in which the cooling fan card was to be placed, did not have an available expansion card, functionality of the computer system is reduced by necessitating removal of an inserted expansion card to provide an empty slot into which the fan card could be inserted. Additionally, because the cooling fan card is coupled to the motherboard, the ambient air within the computer system would be included in the increased airflow, which can, in many instances, be higher in temperature than that of air external of the computer system. Also, because expansion slots within a motherboard are commonly located distant from the microprocessor, the increased airflow is circuitously applied to the microprocessor, which, in many circumstances, may not provide sufficient cooling to the microprocessor. This can be especially prevalent with computer systems having multiple microprocessors, such as rack mount systems.
In another attempt, a larger heat sink with a greater surface area, e.g., taller cooling fins, for heat dissipation may be implemented. It is appreciated that a larger heat sink with taller cooling fins would inherently provide increased heat dissipation. However, in many instances, due to the constraints regarding available vertical space within today's computer systems, a larger heat sink is not a practical or viable solution to the problem. Further, in many instances, even a smaller, conventionally sized heat sink may not fit within the constraints of today's smaller sized computer systems and multiprocessor computer systems.
It is further appreciated that heat sinks are commonly configured with multiple cooling fins. For example, referring to Prior Art FIG. 1, air, e.g., air 2 is forced into heat sink 4 as indicated by airflow direction arrow 3. Heat sink 4 has a bank of cooling fins 5. Air 2 is forced about the surface area of cooling fins 5 providing heat transfer. It is appreciated, however, that the temperature of portions of air 2 which contact those portions of cooling fins 5 farther downstream from airflow 3 has been elevated, inherent to contacting portions of cooling fins 5 further upstream. In some instances, the downstream portions of cooling fins 5 cannot provide sufficient cooling of the now preheated air, which can effect the operation of a computer system.
Furthermore, if increasing the velocity of the airflow forced upon the cooling fins is attempted to provide adequate cooling, this attempt is not without shortcomings associated therewith. While the performance of a heat sink can increase as the velocity of the air passing over the cooling fins increases, with an increase in air velocity, or flow rate, there is an inherent increase in associated pressure drop. Because fans that are utilized to drive air across the cooling fins have a defined pressure drop versus a flow rate, there is a physical limit on the pressure drop a fan can deliver at a given flow rate. This can be addressed by utilizing larger or greater numbers of fins which, as described above, can negatively impact the density of the server or rack mount system. When the airflow contacts the upstream portions of the cooling fins, because of the increased velocity, an increased pressure drop occurs. An increased pressure drop can result in a decrease in volume of the air forced about the surface areas of the cooling fins and effectively reducing the velocity of the airflow, thus reducing the capacity of the cooling fins to dissipate heat.
Hence, many existing heat dissipation devices and methods do not provide sufficient heat dissipation.